Control system for electric elevators



Jan. 30, 1923. 1,443,766

W. 8. SMITH CONTROL SYSTEM FOR ELECTRIC ELEVATORS FILED Aue. 3. 1918. 3 SHEETS'SHEET 1 Jan. 30, 1923.

W. S. SMITH.

CONTROL SYSTEM FOR ELECTRIC ELEVATORS F LED AUu- 3 1 91 8 3 SHEETS'SHEET 2 Jan. 30, 1923. 1,443,766

W. S. SMl-TH, CONTROL SYSTEM FOR ELECTRIC ELEVATORS.

FILED AUG. 3. 1918 3 smears-swan 3 Patented Jan. 30, 1923.

'UNITED STATES WILLIAM S. SMITH, OF CAMBRIDGE, MASSACHUSETTS.

CONTROL SYSTEM. FOR ELECTRIC ELEVATORS.

Application filed August 3, 1918. Serial No. 248,175.

To all whom it may concern Be it known that 1, WILLIAM S. SMITH, a citizen of the United States, residing at Cambridge, in the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Control Systems for Electric Elevators,of which the following is a specification, reference being bad therein to the accompanying drawings.

My invention relates to control systems for electric elevators.

The principal object of my invention is to provide a control system for electric ele-' vators which is capable of use either as an automatic or as a manually operated system.

Another object of the invention is to provide a dual system of such construction that it may be easily changed from one system.

to the other, as for instance by the operation of a switch or similar mechanical device.

A further object is to simplify the arrangement of the various circuits and elements and to combine them that the num ber of parts required will be reduced to a minimum.

An additional object is to provide a simple and effective arrangement of the circuits for controlling the up and down movement of the elevator car.

Other and additional objects of the invention will be more specifically set forth and described hereinafter.

Briefly described. my invention contemplates a dual control system for electric elevators preferably made up of an automatic system, such, for instance, as that shown in United States Letters Patent No. 1,249,682 issued to me December 11, 1917, and certain additional elements necessary to a manually operated system such as an annunciator and a. controller with means for changing the system from an automatic system to a manually operated system and vice versa. I

My invention also contemplates, among other things, improved means for controlling the circuits governing the upwardand downwardmovement of the elevator car.

In the accompanying drawings wherein oneof the various possible embodiments of the invention is illustrated, Figure 1 is a diagrammatic view showing the preferred.

cuits operated in synchronism with the movement of the elevatorcar; Fig. 3 is a View on line 3-3 in Fig. 2 looking from left to right, showing two contact switches in front elevation and the means for operating said switches; and Fig. at is a side elevation, on an enlarged scale, of one of the contact switches.

Fig. 1 of the drawings illustrates the apparatus as adapted to be actuated by a direct current but it may be used in connection .with an alternating current by a proper modification of the magnet construction and the .windings on the same; all of which modifications would be apparent to one versed in the ,art.

In the illustrated embodiment of my invention there is shown a system having four stations or floors but the number of stations or floors may be reduced. or increased by merely subtracting from or'adding certain units to the system.

Referring now more particularly to the drawings in Fig. 1 P andNare positive and negative mains respentive'lyand 5 is the armature of a motor, shown as a shunt motor having a field coil 6 connected to the supply lines by conductors 7 and 8, the circuit being opened and closed by a switch 9. The circuit for operating the motor is across the line as indicated by the conductors 11 and 11*, the circuit being controlled by a reversing switch 12 which will be described hereinafter.

Suitable circuit-closing devices such as push-buttons a a a and a are located at the four floors or stations respectively. When the elevator car is employed for carrying passengers a similar series of pushbuttons b b b and b is installed in the car. The hoistway door on each floor is provided with a contact 0 0 c and 0" respectively, which is open when the door is open and closed when the door is closed so that the system is out of operation unless all the hoistway doors are closed.

Arranged in the push-button circuits are a plurallty of coils d 03 d and d, corre- I sponding in number to the number of floors or stations; said coils having sufficient ampere turns to actuate small floor magnets 6 e 6 and 0*, respectively.

The push-buttons at the stations, when operated, close a circuit from the main P through conductor 13, door contacts 0 0 c and 0, provided they are all closed, conductor 14, thence through coil 03 corresponding to the push-button operated, to corresponding conductors m m m m Said conductors are secured respectively to contacts 72, 73, 74 and 75, which form part of the upper row of contacts of a double-throw switch Sw.

The switch Sw has a middle row of contacts 76, 77, 78, 79, 80, 81 and 82, which form pivot points for the blades of a movable member B which is adapted to be moved into contact with the aforesaid upper row of contacts or with a lower row of contacts for a purpose to be more fully described hereinafter. It may be pointed out that the switch Sw is inserted in the circuits between the floor magnets d (F, (i and (if, and their respective push-button a a a and a.

When the blade member B is in engagement with the upper row of contacts on switch S'w, the automatic control feature of my invention is made available, and the path of the current is from the energized conductor through a blade of the member 18 to the corresponding contact in the middle row. The circuit then continues through conductors 90, 91, 92 or 93, to one contact of the operated push-button. The other contacts of push-buttons a a a and a are connected together and to contact 78 of the middle row of switch Sw by conductor 15 and thence through a blade of the member B to contact 71 of the upper row, conductor 15, contact 16 of the reversing switch, contact member 17, contact 18, conductor 19, contacts 20, 21 and 22 and conductor 23 to the negative main.

- From the foregoing it is clear that inthe automatic feature of my invention the operation of any of the push-buttons a a a or. a will complete the circuit to energizethe corresponding floor magnet (2 or d. v

The contact members 17 and 21 are operated by the reversing switch to open the push-button circuits for reasons and in a manner to be hereinafter explained. When the system is in a normal operative condition, these contact members 17 and 21 are in. amposition closing the push-button circuits across the contacts 16 and 18 and the contacts 20 and 22. The door contacts are so arranged in-this circuit that if any door is opened the circuit cannot be closed by the operation of a push-button. The latter are in parallel circuits, each pushbutton being adapted to close a circuit through its respective coil to actuate its re spective floor magnet. When car push-buttons are employed, they are placed in par.- allel circ'uits with their respective push-buttons at the stations and connected by flexible conductors 24 to those circuits, so that the effect of the operation of the car push-- tively when the magnet is energized and thereby establishes a control circuit through various conductors and switches 7' 3' j, 9' j and j which operate to direct the control circuit to the reversing-switch to start and to stop the motor. These switches are operated by a member C arranged to travel in synclironism with the car and as shown in Figure 1 the member C moves to the right when the car ascends and to the left when it descends. The control circuits adapted to be established by the various floor-magnets may be divided into two main groups, first, a group connecting the switches j 3' and 3' with the contacts 9 h and h and 9 k3 respectively so that the operation of magnet e or e or e closes a circuit to cause the car to descend and, secondly, a group connecting the switches 7', j, and j with the contacts 9 h it and g 71., respectively in order that the operation of the magnet 6 e or c closes a circuit to cause the car to ascend.

The reversing-switch 12 may be of any suitable construction and is shown diagrammatically in Figure 1 as composed of two magnets is and 7: each carrying suitable contacts for closing the motor circuit. The magnet is is included in the first group of control circuits and when it is operated by the closing of any one circuit in this group by the operation of floor-magnet e or e or e contact-pieces 25 and 26 carried by the magnet are. moved into engagement with contacts 27 and 28 and contacts 29 and 30 respectively and thereby closes the motor circuit and admits the current to the motor in such a way as to cause the car to descend. The magnet 70 is included in the second group of control circuits and when operated by the closing of any one circuit in this group through the operation of floor-magnet 6 or e or e contact-pieces 32 and 33 carried by the magnet are thrown into engagement with contacts 34 and 35 and contacts 36 and 37 respectively and in consequence closes the motor circuit and admits the current to the motor insuch a way as to cause the car to ascend.

Both groups of controlcircuits may be connected to the positive main P by a common conductor 40 connected to conductor 14 and through the door contacts to conductor 13 and may be connected to the negative main N by a common conductor 41. Between the points 42 and 43 the control circuits are parallel.

.button after the motor starts and before the car reaches its destination, 1 provide means for maintaining all of the push-button circuits open from the time the reversing-switch is operated until after the car has reached its destination. At the same time I also provide means for maintaining the particular floor magnet which has been operated by the pushing of a push-button to start the motor in an operative postion until the car reaches its destination, otherwise the opening of all the push-button circuits would permit the operated floor-magnet to return to an inop-.

erative position and thereby break the control circuit established to start the motor and the motor would stop. While any suitable 7 means may be employed for opening all the push-button circuits and maintaining the operated floor-magnet in its operated position, I prefer to accomplish these results by providing each floor-magnet with a retainingcoil having sufiicient ampere turns, when energized, to maintain the magnet in an operated position, but not of sufiicient strength to operate it, all of these retaining-coils being in a circuit which is closed and opened by means of contacts carried by the reversingswitch magnets. All of the push-button cir cuits are likewise opened by means of contacts carried by the reversing-switch magnets when the reversing-switch is operated to start the motor. 'In the drawings r r 7' and 1' designate the retaining-coils on the magnets 6 ,6 e and 6' respectively. All of the retaining-coils are connected in series although if desired they may be connected in parallel. These coils are connected to the positive main through the conductor 14Tdo0r contacts and conductor 13 and on the other side are connected to the negative main through conductor 45 and conductor 23. The conductor 45 is connected to a contact 47 on the magnet Z0 and a contact 48 on themagnet is and conductor 23 is connected to contact 46 on the magnet 10 and contact 49 on magnet is the result beingthat when either of said magnets is operated the retaining-coil circuit is closed by the contact-member 17 in 7:: or the contact-member 21 in is. At the same time the operation of either one of these magnets causes the contact-piece 17 or 21 to move out of engagement with the contacts 16 and 18'or 20 and 22 and to open all the push-button circuits.

i order to transfer from the automatic control system to the operator controlled system, the blade member B is disengaged from the upper row of contacts and swung into engagementwith the lower row 83, 84, 85, 86, 87, 88, and 89 respectively. The above mentioned action breaks the circuits through conductors m 7213, m and m, and

consequently it will be seen that as long as blademember B is out of engagement with the upper row of contacts, no current can flow through any of the coils on floor magnets 6 e and 6. When the blade member B of the switch Sw is in engagement with the lower row of contacts, as above mentioned, the operator controlled feature of my invention is available, and this feature contemplates the use of a controller and annunciator in the car, together with certain elements of the automatic controlled system.

In the operator controlled feature of my invention beginning at the positive main at the point 99, the circuit follows the conductor 13, through switches at the hoistway doors c c 0 and c, if they are all closed, along the conductors 14 and 40 to the point 42 where the circuit branches. One branch passesthrough the magnet K, conductor 69, switch j and conductor 95 to a contact on the controller Op. The other branch passes from the junction 42, through the magnet K conductor 62, switch j, conductor 96 to another contact on the controller Op. The controller Op is provided with a movable handle H and contact adapted to be moved by the operator into contact with the conductor 95 Or 96, 'asmay be desired. The contact on the handle H is connected by conductor 94 to contacts 84 and 83 in the lower row of switches Sw. If the contact on the handle H has been moved into engage ment with the contact with which-the conductor 95 is connected, current Will then flow from the conductor 95, through conductor 94, contacts 83 and 84. The current may then pass through corresponding blades of the member B contacts 76 and 77 in the middle row and thence through eitherconductors 45 or 15 to the reversing-switch 12. It will be seen, however, that the circuit through the conductor 45 is broken at contacts 48 and 49, and, therefore, the current in this case will pass from conductor 15 through contact 16, contact member 17, contact 18, conductor 19, contact 20 to contactmember 21, contact 22 and conductor 23 to the negative side of the line, thus completing the circuit, and energizing the magnet K. The reversing-switch 12 now opcrates in the manner which has already been described in connection with the automatic controlled feature of my invention, to cause the motor to operate so as to move the car" in a downward direction. On the other hand, if the contact on the handle H of the controller Op is moved into engagement with the contact to which the conductor 96 is connected, the magnet K is energized and the reversing-switch operates to cause the motor to move the car in an upward direction. v

The annunciator An of the operator controlled system is adapted to operate on the line voltage and provides a series of inclicators equal in number to the stations served by the car and connected by suitable con ductors to a like number of contacts 86, 87, 88 and 89 in the lower row on the switch Sw. A conductor 97 is joined to a positive main, or to conductor 13, and acts as a common connection to one side of all-of the indicating elements in the annunciator. When any of the push-buttons at the hoistway doors are operated, a circuit is established from the positive main through the conductor 97, through the indicating element of the annunciator corresponding to the operated push-button, thence to the contact on the lower row of the switch Sw corresponding to the actuated element of the annunciator and thence through the push-button to conductor 15 which is connected to contact 78 in the middle row on switch Sw,through the corresponding blade of member B to contact 85, and thence along conductor 98 to thenegative main.

It will now be seen that push buttons a a a a and a 'at the hoistway doors are used in both the automatic and the operator controlled features of my invention,

and in the last mentioned feature the operation of any one of said push-buttons will actuate the corresponding indicating element on the annunciator A12.

It may be further pointed out that the contacts at the hoistway doors, c c 0 and of. switches 7' and j, magnets is .-and k reversing switch '12 and operating motor 5 are all common to both features of my invention, In addition, it will be seen that I have taken most of the elements of the automatic controlled system disclosed in my Patent No. 1,249,682, issued December 11, 1917, and, by the addition of switch Sw, annunciator An and controller Op have made it possible for the car to be operator controlled when desired.

In Figure 2 is shown a front elevation of my improved device for controlling the up and down circuits, which comprises a plurality of contact switches mounted on two separate supports included in the up and down circuits respectively, and means for operating the switches in synchronism with the up and down movement of the elevator car. Any suitable form of frame may be provided for supporting the mechanism, and as shown the frame is made up of two end pieces 130.connected together by side pieces 131; the frame being rectangular in general form. On the inner face of each end piece 130 is fastened a block 132 and to these blocks are secured .by screws 133 supporting bars 134, both of said bars being insulated from the blocks of insulation 135 and being current carrying members; one of said bars being included in the up circuits and the other in the down circuits. Upon each bar is adj ustably mounted and secured thereto a plurality of contact. switches, the number on each bar being one less than the number of floor landings in the elevator system. In the. drawings my device is shown as adapted to a system having five floors or five landings; this number, of course, may be increased or decreased to conform to the number of landings in the particular system to which it is applied. As shown in Figure 2, the contact switches on the right hand bar control the down circuits and the switches on the left hand bar con trol the up circuits, which requires that the cont-r01 switches on the right hand bar overlap those on the left hand bar or vice versa.

For operating the switches in synchronism .with the movement of the elevator car a screw 101 is rotatably mounted in the two blocks 132; said screw having its lower end projecting below the lower end piece 130 of the frame and provided with a bevelled pinion 137 which meshes with a bevelled gear 138 fastened to a shaft 140 rotatably mounted in bearings 141 secured by nuts 142 to brackets 143 on the frame. The screw 101 is loosely threaded through a nut 102 carrying a pin 103 upon which a roll 104 of insulating material is mounted; the screw and roll being so arranged with relation to the contact switches that when the screw is rotated and the roll travels backward and forward, dependent upon the direction in which the screw is turned, it operates the contact switches to open and close, 0r vice versa, the up and down circuits. The nut or carrier is provided with lateral extending wings 145 riding on rails 146 comprising a part of the side pieces of the frame, thereby preventing the nut turning. The bevelled gears 137 and 138 and 'the thread of the screw are of such sizes and pitch respectively that the nut 102 is caused to move in synchronism with the elevatorcar and thereby to operate the contact switches at appropriate times. The end piece 130 and side pieces 131 of the frame may be provided with edge recesses 150 and 151 respectively, to permit a suitable cover (not shown) to be mounted on the frame to protect the mechanism from dirt and dust.

Two of the contact switches for controllin the up circuits appear in Fig. 3, the one at he left in open or off position, and the one at the right in closed or on position. All of the switches for controlling the up and down circuits are similar in construction and comprise a body or main member 105, having a portion 106 projecting to the right,

(see Fig. 4) near its lower edge, adapted for engagement with the corresponding edge of its supporting bar. The lug or ear 107 projects to the right from the upper part of the main member 105 and there is threaded therein a cone-pointed screw 108 which acts against the upper edge of the supporting bar to retain the switch firmly in position after it has been adjusted for operation. Pivotally mounted on the pin 109, which extends from the opposite side of the body 105, is shown a contact member having two operating fingers 110 adapted to operatively engage with the roll 103, and a contact finger 111 adapted to engage with a second con tact member 112. Torsion spring 113 serves to hold the contact member in the open or off position against a stop indicated at 114. Secured to the body 105 is shown a piece of insulating material 115 which has mounted thereon a binding post 116 connected by means of a metallic strip 117 to abracket 118 whichserves as a support and stop for the second contact member 112, which is retained against lateral movement by the pin 119. Passing through the bracket 118 and contact member 112 is shown a springpressed pin 120, which normally holds said contact member against bracket 118 when the switch is in the-open or off position, as shownat the left in Fig. 2. When the contact finger 111 has been moved into operative engagement with the contact member 112, said contact member is raised against the pressure of the spring pin 120 which pressure is great enough to overcome the pressure exerted by the spring 113 and holds the contact finger 111 in closed or on position until such time as the, roll 104 shall cooperate with one of the operating fingers 110 to break the circuit. When the switch is in the 0n.or closed position, the path of current is from the supporting bar through the body of the switch to the first contact member 111, thence through the second contact member112, bracket 118 and strip 117 to binding post 116. When the switch is in open position the circuit is open, due to the second contact member 112 and its associated parts being mounted on piece 115, which insulates them from the body 105.

In the operation of my'device, the blade member B being placed in engagement with the upper row of contacts of switch S w establishes a circuit for the automatic controlled system of my invention as already described. .This feature then operates as set forth in my Patent No. 1,249,682. When it is desired to dispense with the automatic control and to have the car controlled by an operator in the car, the blade member B of switch Sw is withdrawn from the upper row of contacts and placed in engagement with the lower row. The firstefi'ect of this movement is to disconnect coils d d, d

quickly and a? and coils e e e and e and their associated circuits, from the source of electric supply. A further efl'ec-t of-said move ment is to establish the circuits from the controller in the car through switches 7' and j, coils Z", and in controlling the reversing switch 12 which, in turn, controls the operating motor. At the same time, the circuits are established from the positive main to the annunciator which is controlled by push-buttons of the automatic, system as her'einbefore described. On receiving a signal' from the annunciator, the operator may then manipulate the handle it of the controller ()p to cause the car to ascend or descend as the case may be.

Some of the advantages of my dual system of control are that a simple and eflicient automatic controlled system and a simple and efficient operator controlled system are provided, are easily installed and the transfer from one system to the other is and easily accomplished. The switches on the hoistway doors provide a safeguard against accident when either system is used and the switches and 7' provide a. safeguard against the over-running of the car when said car is controlled by an operator. The fact that the pushbuttons at the hoistway doors are used to control the car in the automatic system and to complete the annunciator circuits in the operator controlled system, makes for lower cost and great convenience in operation.

Another advantage of my dual controlled system is that by it an automaticelevator is made suitable for heavy service. In an oflice building, for instance, an operator may be employed in the car during the usual business hours and in the early morning or late evening the control of the car may be transferred to the automatic system, thus providing the tenants with an eflicient elevator system without the expense of any operator to the owners of the property.

It is to be understood that my invention may be embodied in other forms of construction than that herein shown and described and except where specifically limited in the following claims it is my intention to claim it broadly.

What I claim is 1. A dual control system. for electric elevators having, in combination with a motor for operating the car in either direction and a reversing switch for starting and stopping said motor, an automatic electrical control system comprising a push-button for each floor or station, a magnet for each floor or station, each floor magnet being provided with an actuating coil in c rcuit with its respective push-button and being provided with a retaining coil, a suitable circuit including the retaining coils on said floor magnets and means whereby said last mentioned circuit is closed and said push-button circuits are opened whenever said reversing switch is operated to start the motor; an operator controlled system comprising a manually operated controller, an annunciator, suitable circuits extending from said controller to the reversing switch, means comprising a double-throw switch for changing from one system to the other and means whereby the push-buttons of the automatic control system may be utilized to actuate the annunciator when the car is controlled by an operator.

2. A dual controlling system for electric elevators having, in combination with a motor for operating the car in either direction and a reversing switch for starting and stopping said motor, an automatic controlled system comprising a push-button for each floor or station, a magnet for each floor or station, each floor magnet being provided With an actuating coil in circuit with its respective push-button and being provided with aretaining coil, a suitable circuit including the retaining coil on said floor magnet and means whereby said last mentioned circuit is closed and said p-us'hbutton circuits areo'pe'ned whenever said reversing switch is operated to start the motor, an operator controlled system and means comprising a double-throw switch for transferring from one system to the other at will.

3. A dual controlling system for electric elevators having, in combination with a motor for operating the car in either direction and a reversing switch for starting and stopping said motor, an automatic pushbutton controlled system and an operator controlled system comprising a manually operated controller, an annunciator, a pushbutton for each floor or station, suitable circuits extending from said controller to operate said reversing switch, said circuits extending from said push-buttons to said annunciator, and means comp-rising a double-throw switch for transferring from one control system to the other at will.

4. In an apparatus for controlling elevators, the combination of a push-button switch at each landing, electrical devices for causing the car to come to and stop at the landing at which a push-button is operated, a signalling device for signalling the operator in the elevator car when a push-button is operated and a manually operated controller switch by means of which the pushbuttons at the floor landings may be disconnected from said electrical devices and connected to said signalling device and vice versa.

5. In an apparatus for controlling elevators, the combination of an automatic pushbutton system comprising a push-button at each landing and a plurality of circuits for controlling the movement of the elevator by said push-buttons, an operator controlled system comprising a manually operated controller, a plurality of circuits for controlling the movement of the elevator by said controller and means for signalling the operator from said floor landings, and manually operated means for changing from one system to the other.

6. In an apparatus for controlling elevators, the combination of an automatic pushbutton system comprising a push-button at each landing and a plurality of circuits for controlling the movement of the elevator by said push-buttons, an operator controlled system comprising a manually operated c0ntroller, a plurality of circuits for controlling the movement of the elevator by said controller, an annunciator and a plurality of circuits for operating said annunciator by said push-buttons, and manually operated means for changing from one system to the other.

In Witness whereof, I hereunto set my hand this sixth day of June, 1918.

WILLIAM S. SMITH. 

